In recent years, an image forming apparatus such as a printer or a multi-function peripheral has a mode called an energy-saving mode for shifting to a status where less power is consumed than a normal standby status. The energy-saving mode is generally realized by supplying power only to a certain part of an entire device.
Such an image forming apparatus is installed in a network environment where many information devices including a computer are connected and is required even in the energy-saving mode to restore from the energy-saving mode by supplying power to a main body when a print request or the like is received from an information device.
The request which requires an operation of the main body includes a status request (status inquiry request) of the image forming apparatus in addition to the above-described print request. In recent years, there is the case where a computer connected to a network environment uses an application called a status monitor for making such a request and monitors a status of the image forming apparatus. Such an application often requests to notify the image forming apparatus regularly of the status information so that the status of the image forming apparatus can be presented to a user at any time.
Normally, when the main body of the image forming apparatus is in a standby status, a network portion of the image forming apparatus by giving inquires to the main body of the image forming apparatus acquires the requested status information to respond.
In addition, when such a status request is received in the energy-saving mode where power is not supplied to the main body, the network portion, if not having any means, needs to supply power to the main body for restoration and acquire the status information for response whenever the status request (that is, the status inquiry) is sent. In the case where the network environment has many external apparatuses which introduced applications for making such a status request, the image forming apparatus supplies power to the main body for restoration with respect to all of the requests, which results in great difficulty in continuing the energy-saving mode.
There are various kinds of the status information concerning the image forming apparatus, including an operational status of online/offline as a system, an open/close status of a cover, a remaining quantity of sheets in a tray and a sheet size. It is needless to say that information which may change in the energy-saving mode is included.
As a technology for solving such a difficulty to continue the energy-saving mode (power-saving status), Japanese Laid-Open Patent Publication No. 2006-113947 discloses that an inquiry about a status is not made from a computer side to an image forming apparatus but a status monitor which receives status information transmitted from the image forming apparatus regularly is mounted in the computer.
Moreover, Japanese Laid-Open Patent Publication No. 2004-34488 discloses a technique for solving the difficulty to continue the power-saving status not by an application program on a computer side but by a main body of an image forming apparatus. This image forming apparatus uses a sub-CPU (Central Processing Unit), which is different from the one used in a normal operation, in a power-saving status to respond to a status request without activating the main body (main chip). In this case, a part of a status detecting sensor of a controller for a scanner part and a printing part is enabled even in the power-saving status so that a change in the status can be recognized even if the sub-CPU is in the power-saving status, and thereby, it becomes possible to transmit status information to the computer in keeping the power-saving status.
However, in the technique described in Japanese Laid-Open Patent Publication No. 2006-113947, a part of the computer in a network environment incorporates a unique application program which is not a common status monitor, and when the application program makes a status request to the image forming apparatus frequently, it is difficult for the image forming apparatus to continue the power-saving status.
Moreover, in the technique described in Japanese Laid-Open Patent Publication No. 2004-34488, standby power for operating the status detecting sensor regularly is necessary even in the power-saving status, and if the status detecting sensor is completely turned off in the power-saving status, the status information is not updated until the main chip is restored (that is, until the main body of the image forming apparatus is restored).